JPS641767B2 - - Google Patents
Info
- Publication number
- JPS641767B2 JPS641767B2 JP57150512A JP15051282A JPS641767B2 JP S641767 B2 JPS641767 B2 JP S641767B2 JP 57150512 A JP57150512 A JP 57150512A JP 15051282 A JP15051282 A JP 15051282A JP S641767 B2 JPS641767 B2 JP S641767B2
- Authority
- JP
- Japan
- Prior art keywords
- filter
- light
- scanning
- scanned
- optical system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 claims description 29
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 4
- 230000004907 flux Effects 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
- H04N1/113—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors
- H04N1/1135—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors for the main-scan only
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Mechanical Optical Scanning Systems (AREA)
- Facsimile Scanning Arrangements (AREA)
- Exposure Or Original Feeding In Electrophotography (AREA)
Description
【発明の詳細な説明】
本発明は、レーザ等を光源に用いた記録装置又
は読取装置等の走査光学系に関するものであり、
更に詳細に述べれば、レーザ等の光源からの光束
を偏向器で走査し、被走査面をビームスポツトで
走査するいわゆるフライングスポツトタイプの走
査光学系或いは被走査面の各部分からの光束を偏
向器を介して受光手段で順次受けることにより被
走査面を走査するいわゆるフライングイメージタ
イプの走査光学系に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning optical system such as a recording device or a reading device using a laser or the like as a light source.
More specifically, it is a so-called flying spot type scanning optical system in which a beam from a light source such as a laser is scanned by a deflector and the surface to be scanned is scanned with a beam spot, or a beam spot from each part of the surface to be scanned is scanned by a deflector. This invention relates to a so-called flying image type scanning optical system that scans a surface to be scanned by sequentially receiving light through a light receiving means.
従来、走査光学系においてはフイルターが種々
の目的で使用されているが、これ等のフイルター
は通常走査光学系内の光ビームが偏向走査を受け
ない位置に配されるのが常套の手段である。然し
ながら、例えばフライングスポツトタイプの走査
光学系を採用するレーザビームプリンターにおい
ては、光源部と偏向手段との間にフイルターを配
すると、レーザビームはフイルターの常に同じ位
置を通過する為にフイルターが劣化し、フイルタ
ー本来の作用を損なうことがあつた。又、同じ強
度のビームスポツトで被走査面を走査する様な必
要性がある場合、偏向手段と被走査面の間に走査
用の結像レンズ系が存在する様な場合には、走査
用レンズの中心部と周辺部ではビームスポツトの
強度が異なる結果を生じる。斯様な場合には、フ
イルターを偏向手段と被走査面との間に配するこ
とが必要となつてくる。又、フライングイメージ
タイプの走査光学系においても、被走査面の各部
分からの光束を、等しい光量で受光手段により検
出したい場合には被走査面と偏向手段との間に、
フイルターを配する必要が生じる場合がある。 Conventionally, filters have been used for various purposes in scanning optical systems, but these filters are normally placed at positions in the scanning optical system where the light beam is not subjected to deflection scanning. . However, for example, in a laser beam printer that employs a flying spot type scanning optical system, if a filter is placed between the light source and the deflection means, the laser beam always passes through the same position of the filter, which may cause the filter to deteriorate. , the original function of the filter could be impaired. Also, if it is necessary to scan the surface to be scanned with a beam spot of the same intensity, or if there is an imaging lens system for scanning between the deflection means and the surface to be scanned, the scanning lens The intensity of the beam spot will differ between the center and the periphery. In such a case, it becomes necessary to arrange a filter between the deflection means and the surface to be scanned. Also, in a flying image type scanning optical system, if it is desired to detect the light flux from each part of the scanned surface with the same amount of light by the light receiving means, there is a
It may be necessary to install a filter.
従来フイルターは直線平面で使用されており、
斯様なフイルターを偏向手段と被走査面との間に
配した走査光学系の部分概略図を第１図に示す。
第１図において、レーザ光源等からの光束１は矢
印の方向に回転するポリゴンミラー２に入射し、
反射され走査光３となる。走査光３は直線平面フ
イルター４を通過し、被走査面５を走査する。 Conventionally, filters are used in a straight plane,
FIG. 1 shows a partial schematic diagram of a scanning optical system in which such a filter is arranged between the deflection means and the surface to be scanned.
In FIG. 1, a light beam 1 from a laser light source or the like is incident on a polygon mirror 2 rotating in the direction of the arrow.
It is reflected and becomes scanning light 3. The scanning light 3 passes through a linear plane filter 4 and scans a surface to be scanned 5 .
フイルターの光の吸収量は、フイルター内の光
路長に比例する。第１図においてフイルターに垂
直に入射する走査光３ａのフイルター内光路長は
フイルターの厚みをｔとするとｔである。入射角
αで入射する走査光３ｂのフイルター内光路長ｌ
は
ｌ＝ｔ／cosθただしsinα／sinθ＝ｎ
ｎ：フイルターの屈折率
となり、ｔ＜ｌである為、被走査面５での走査光
３ｂは３ａより光量的に少なくなる。従つて、入
射角αが小さくなる程透過光量が少なくなり、走
査域に光量ムラが生じる。このことは、フライン
グイメージ走査光学系においては受光素子に入射
する光量のムラとなつて現われる。 The amount of light absorbed by a filter is proportional to the optical path length within the filter. In FIG. 1, the optical path length within the filter of the scanning light 3a that enters the filter perpendicularly is t, where t is the thickness of the filter. Optical path length l in the filter of the scanning light 3b incident at the incident angle α
is l=t/cosθ, where sinα/sinθ=n n: refractive index of the filter, and since t<l, the amount of scanning light 3b on the scanned surface 5 is smaller than that of 3a. Therefore, as the incident angle α becomes smaller, the amount of transmitted light decreases, causing unevenness in the amount of light in the scanning area. In the flying image scanning optical system, this appears as unevenness in the amount of light incident on the light receiving element.
又、第２図に示す様に、フイルター４のａの位
置に入射した走査光３は、ａ→ｂ→ｃの経路で通
過するのであるが一部はフイルター４のｂの内面
で反射され、ｂ→ｄ→ｅ→ｆと反射されるものが
ある。走査光が単色光の場合この反射光ａ→ｂ→
ｄ→ｅ→ｆと透過光ｄ→ｅ→ｆにより光の干渉を
起こす。つまりこれらの光路長差が走査光である
単色光の半波長の偶数倍のとき強め合い、奇数倍
のとき弱め合う。この為に、走査域に光量の強弱
の縞模様ができてしまう。この光量ムラは走査角
が大きくなればなる程密になり目立ちやすいもの
となる。 Furthermore, as shown in FIG. 2, the scanning light 3 that enters the position a of the filter 4 passes through the path a → b → c, but a part of it is reflected by the inner surface of the filter 4 at position b. There is something that is reflected as b → d → e → f. If the scanning light is monochromatic light, this reflected light a→b→
Light interference occurs due to d→e→f and transmitted light d→e→f. In other words, when the difference in optical path length is an even number multiple of the half wavelength of the monochromatic light serving as the scanning light, they strengthen each other, and when the difference is an odd number, they weaken each other. For this reason, a striped pattern of light intensity is formed in the scanning area. The larger the scanning angle, the denser and more noticeable this light amount unevenness becomes.
本発明の目的は、上述した欠点を除去した走査
光学系を提供することにある。 An object of the present invention is to provide a scanning optical system that eliminates the above-mentioned drawbacks.
この目的を達成する本発明は、偏向手段に入射
するレーザービームを所定の方向に走査する光学
系において、前記偏向手段と、被走査面の間に
は、偏向手段に凹面を向けた実質的に円弧状のフ
イルターを有し、このフイルターによるレーザー
ビームの吸収量は走査方向で略等しいことを特徴
とするもの、及び被走査面の各部分からのレーザ
ービームを偏向手段により順次受光手段に導く走
査光学系において、前記被走査面と偏向手段の間
には偏向手段に凹面を向けた実質的に円弧状のフ
イルターを有し、このフイルターによるレーザー
ビームの吸収率は偏向手段による偏向方向で略等
しいことを特徴とするものである。尚、本発明で
言うフイルターとは、NDフイルター、色分解フ
イルター等の様に、光束が通過する際に、いくら
かの光量でも吸収する様なものはすべて含まれ
る。 To achieve this object, the present invention provides an optical system for scanning a laser beam incident on a deflection means in a predetermined direction, in which a substantially concave surface facing the deflection means is provided between the deflection means and the surface to be scanned. A scanning device having an arc-shaped filter, in which the amount of absorption of the laser beam by the filter is approximately equal in the scanning direction, and a scanning device in which the laser beam from each part of the surface to be scanned is sequentially guided to the light receiving device by a deflection device. The optical system includes a substantially arc-shaped filter with a concave surface facing the deflection means between the scanned surface and the deflection means, and the absorption rate of the laser beam by this filter is approximately equal in the direction of deflection by the deflection means. It is characterized by this. Note that the filter referred to in the present invention includes any filter that absorbs even a certain amount of light when the light beam passes through it, such as an ND filter or a color separation filter.
第３図は本発明に係る走査光学系の一実施例を
示す概略図である。１１は半導体レーザの如き光
源部であり、該光源部を射出された光束１２はポ
リゴンミラー１４により偏向走査光１３となり、
フイルター１６を介して被走査面１５に到達す
る。フイルター１６は、ポリゴンミラー１４によ
り光束１２が偏向作用を受ける位置P1、正確に
言うならばこのP1なる位置は偏向器の回転に伴
つて多少移動するのでこの位置P1の近傍の範囲
内の任意の位置を中心点とする円弧状の形状を有
する。従つて、ポリゴンミラー１４で偏向作用を
受けた各々の走査光１３は、フイルター１６にほ
ぼ垂直に入射するので、隣接する各光束間で干渉
作用を起こさない。又、フイルター１６の厚みを
均一に保てば、フイルター１６を通過する各々の
光束の光路長は等しくなるので被走査面上での光
量ムラを防止出来る。 FIG. 3 is a schematic diagram showing an embodiment of the scanning optical system according to the present invention. Reference numeral 11 denotes a light source section such as a semiconductor laser, and a light beam 12 emitted from the light source section becomes deflected scanning light 13 by a polygon mirror 14.
The light reaches the scanned surface 15 via the filter 16. The filter 16 is located at a position P 1 where the light beam 12 is deflected by the polygon mirror 14. To be more precise, this position P 1 moves somewhat as the deflector rotates, so the filter 16 is located within a range near this position P 1 . It has an arcuate shape with its center point at an arbitrary position. Therefore, each scanning light beam 13 that has been deflected by the polygon mirror 14 enters the filter 16 almost perpendicularly, so that no interference occurs between adjacent light beams. Furthermore, if the thickness of the filter 16 is kept uniform, the optical path lengths of the respective light beams passing through the filter 16 will be equal, thereby preventing unevenness in the amount of light on the scanned surface.
第３図に示す光学系においては、ポリゴンミラ
ー１４と被走査面１５との間には、通常走査用の
結像レンズ系、例えばｆ−θレンズとかｆ−
arcsinθレンズが配される。これ等のレンズとフ
イルター１６との配置上の位置関係には特に制限
はないが、走査用レンズとポリゴンミラー１４の
間にフイルター１６を配すれば、フイルター１６
を小型化できる。一般に、斯様な走査用レンズは
光軸より周辺部では光量の低下が見られるので、
この現象をフイルター１６の透過率で部分毎に変
化させることにより補正することも可能である。 In the optical system shown in FIG. 3, an imaging lens system for normal scanning, such as an f-theta lens or an f-
An arcsinθ lens is arranged. There is no particular restriction on the positional relationship between these lenses and the filter 16, but if the filter 16 is placed between the scanning lens and the polygon mirror 14, the filter 16
can be made smaller. Generally, with such a scanning lens, the amount of light decreases at the periphery from the optical axis.
It is also possible to correct this phenomenon by changing the transmittance of the filter 16 for each section.
出願人の行なつた実験によれば、光源を半導体
レーザー，ポリゴンミラーより被走査面までの距
離を220mm，フイルターをコダツク社製ゼラチン
NDフイルター（透過率約70％，厚み約80μ）と
した時、第１図に示す従来の走査光学系の構成に
おいてはα≒20゜の場合、走査光３ａと３ｂの光
量差が約６％，走査光３ｂ付近での被走査面５上
での光の干渉による光量ムラのピツチは約８mmで
その光量強弱差は約８％と観測された。 According to experiments conducted by the applicant, the light source was a semiconductor laser, the distance from the polygon mirror to the scanned surface was 220 mm, and the filter was a gelatin filter manufactured by Kodatsu.
When using an ND filter (transmittance of about 70%, thickness of about 80μ), in the configuration of the conventional scanning optical system shown in Fig. 1, when α≒20°, the difference in light intensity between scanning beams 3a and 3b is about 6%. It was observed that the pitch of unevenness in light intensity due to light interference on the surface to be scanned 5 near the scanning light 3b was about 8 mm, and the difference in light intensity was about 8%.
これに対して第３図に示される装置において
は、フイルターへの入射角を約8゜以内におさえれ
ば、フイルター内の光路長差による光量ムラは数
％以下になり、又、光の干渉による光量ムラのピ
ツチも30数mmと大きくなり、目立たないものとな
り、実用上問題とならなくなつた。特に、フイル
ターに入射する光束がほぼ垂直になれば、光量
差、光量ムラ等はいつさいなくなつた。 On the other hand, in the device shown in Fig. 3, if the angle of incidence on the filter is kept within about 8 degrees, the unevenness in the amount of light due to the difference in optical path length within the filter will be less than a few percent, and the unevenness due to light interference will be reduced to less than a few percent. The pitch of uneven light intensity has increased to more than 30 mm, making it less noticeable and no longer a practical problem. In particular, when the light flux entering the filter became almost perpendicular, differences in light intensity and unevenness in light intensity disappeared.
第３図に示す、半導体レーザ光源１１をフオト
センサーで置き換えて、被走査面１５からの光束
をポリゴンミラー１４を介してフオトセンサーに
導びく読取り装置を構成した場合、被走査面１５
とポリゴンミラー１４との間にフイルターを設け
る必要がある場合には、上述した構成のフイルタ
ー１６を設けることが望ましい。 When the semiconductor laser light source 11 shown in FIG. 3 is replaced with a photo sensor to configure a reading device that guides the light flux from the scanned surface 15 to the photo sensor via the polygon mirror 14, the scanned surface 15
If it is necessary to provide a filter between the polygon mirror 14 and the polygon mirror 14, it is desirable to provide the filter 16 having the above-described configuration.
第３図に示す実施例では、フイルターに入射す
る光束が、フイルターに対して垂直に入射する様
に、フイルターの面を曲面状に形成したものであ
るが、第４図に示す様に、フイルター１７に入射
する光束が出来るだけフイルターに垂直に入射す
る様に、平板状のフイルターを複数回折り曲げて
いる。この様にフイルターを複数回折り曲げるこ
とにより、フイルター１７を第３図に示したフイ
ルター１６の様に、出来るだけ円弧状に近い形に
形成したものである。フイルター１７は前述した
如く一枚の平板フイルターを複数回折り曲げて形
成しても、又、複数枚の小さな平板状フイルター
を円弧状にならべて形成しても良い。 In the embodiment shown in FIG. 3, the surface of the filter is formed into a curved shape so that the light beam incident on the filter is perpendicular to the filter, but as shown in FIG. The flat filter is bent multiple times so that the light beam incident on the filter 17 is incident as perpendicularly to the filter as possible. By bending the filter multiple times in this manner, the filter 17 is formed into a shape as close to an arc as possible, like the filter 16 shown in FIG. 3. The filter 17 may be formed by bending a single flat filter multiple times as described above, or may be formed by arranging a plurality of small flat filters in an arc shape.
以上、述べた様に、本発明に係る走査光学系で
は、偏向手段と被走査面との間に配する色分解フ
イルターや光量を調整する為のNDフイルター等
のフイルターにより生じる、光量ムラ，干渉縞等
の悪影響を簡易な構成により除去すると言う優れ
た効果を有するものである。 As described above, in the scanning optical system according to the present invention, light intensity unevenness and interference caused by filters such as a color separation filter arranged between the deflection means and the scanned surface and an ND filter for adjusting the light intensity, This has the excellent effect of eliminating adverse effects such as stripes with a simple configuration.
第１図及び第２図は従来の走査光学系を示す
図、第３図及び第４図は各々本発明に係る走査光
学系の一実施例を示す図。
１１……光源、１３……偏向走査光、１４……
ポリゴンミラー、１５……被走査面、１６，１７
……フイルター。
1 and 2 are diagrams showing a conventional scanning optical system, and FIGS. 3 and 4 are diagrams each showing an embodiment of the scanning optical system according to the present invention. 11...Light source, 13...Polarized scanning light, 14...
Polygon mirror, 15...Scanned surface, 16, 17
...filter.
Claims (1)
方向に走査する光学系において、 前記偏向手段と、被走査面の間には、偏向手段
に凹面を向けた実質的に円弧状のフイルターを有
し、このフイルターによるレーザービームの吸収
量は走査方向で略等しいことを特徴とする走査光
学系。 ２ 被走査面の各部分からのレーザービームを偏
向手段により順次受光手段に導く走査光学系にお
いて、 前記被走査面と偏向手段の間には偏向手段に凹
面を向けた実質的に円弧状のフイルターを有し、
このフイルターによるレーザービームの吸収率は
偏向手段による偏向方向で略等しいことを特徴と
する走査光学系。[Scope of Claims] 1. In an optical system that scans a laser beam incident on a deflection means in a predetermined direction, a substantially arcuate shape with a concave surface facing the deflection means is provided between the deflection means and the surface to be scanned. 1. A scanning optical system comprising a filter, the amount of laser beam absorbed by the filter being substantially equal in the scanning direction. 2. In a scanning optical system that sequentially guides a laser beam from each part of a surface to be scanned to a light receiving means by a deflection means, a substantially arc-shaped filter with a concave surface facing the deflection means is provided between the surface to be scanned and the deflection means. has
A scanning optical system characterized in that the absorption rate of the laser beam by the filter is approximately equal in the direction of deflection by the deflection means.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57150512A JPS5940621A (en) | 1982-08-30 | 1982-08-30 | Scanning optical system |
| US06/525,714 US4687283A (en) | 1982-08-30 | 1983-08-23 | Scanning optical system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57150512A JPS5940621A (en) | 1982-08-30 | 1982-08-30 | Scanning optical system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5940621A JPS5940621A (en) | 1984-03-06 |
| JPS641767B2 true JPS641767B2 (en) | 1989-01-12 |
Family
ID=15498478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57150512A Granted JPS5940621A (en) | 1982-08-30 | 1982-08-30 | Scanning optical system |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4687283A (en) |
| JP (1) | JPS5940621A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6392913A (en) * | 1986-06-20 | 1988-04-23 | Matsushita Electric Ind Co Ltd | Optical recorder |
| US5010353A (en) * | 1986-07-04 | 1991-04-23 | Konica Corporation | Laser recorder with integrally molded deflector |
| JP3093337B2 (en) * | 1991-07-15 | 2000-10-03 | キヤノン株式会社 | Scanning optical device |
| DE10225387B4 (en) * | 2002-06-07 | 2007-09-20 | Mlt Micro Laser Technology Gmbh | Device for substrate treatment by means of laser radiation |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1900966A (en) * | 1927-12-27 | 1933-03-14 | Wilmot R Evans | Projection apparatus |
| US2384578A (en) * | 1943-03-10 | 1945-09-11 | Bausch & Lomb | Optical element |
| US3558208A (en) * | 1967-10-11 | 1971-01-26 | Rca Corp | Optical compensating filter with selective radial absorption distribution |
| US3785720A (en) * | 1972-05-23 | 1974-01-15 | W Kyryluk | Filter for obtaining a three-dimensional effect |
| DE2350281C2 (en) * | 1973-10-06 | 1982-04-01 | Fa. Carl Zeiss, 7920 Heidenheim | Wide-angle mirror lens for reproduction and projection in a finite image scale |
| DE2918283C2 (en) * | 1979-05-07 | 1983-04-21 | Carl Baasel, Lasertechnik KG, 8000 München | Device for substrate treatment with a rotating mirror or the like. |
| JPS6055809B2 (en) * | 1979-11-26 | 1985-12-06 | 大日本スクリ−ン製造株式会社 | Optical scanning method |
| JPS5723914A (en) * | 1980-07-21 | 1982-02-08 | Canon Inc | Recorder |
| US4466699A (en) * | 1982-01-22 | 1984-08-21 | Honeywell Inc. | Curved tunable Fabry-Perot filter |
-
1982
- 1982-08-30 JP JP57150512A patent/JPS5940621A/en active Granted
-
1983
- 1983-08-23 US US06/525,714 patent/US4687283A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US4687283A (en) | 1987-08-18 |
| JPS5940621A (en) | 1984-03-06 |
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